On 22 May 2002, Dan Connolly wrote:
> > I ask
> > that the WebOnt WG discuss whether to send a polite note back rejecting
> > this interpretation of our work.
>
> I don't think we should.
FWIW, Peter's dissatisfaction with my note (which wasn't addressed here)
is noted.
I continue to regard the WebOnt language (and the RDF 1.0 syntax, and it's
MT, and RDFS) as a component of the wider Resource Description Framework,
but don't propose we take time up discussing labels here.
(<onlyhalfjoking>We used to call this effort the Platform for Internet
Content Selection; maybe we could go back to that name if folks really
don't like the RDF TLA?</onlyhalfjoking>)
[...]
> A consumer of the above document either or does or doesn't grok
> DAML+OIL semantics; it can come to more of the relevant conclusions
> if it applies DAML+OIL axioms, but since everything is monotonic,
> there's no harm done if it doesn't apply those axioms.
>
> This is the principle of partial understanding in action.
> I have tried to make this point in the past...
> http://lists.w3.org/Archives/Public/www-webont-wg/2002Mar/0339.html
> but I'm not having much luck.
How about we try to think about this issue in forward-looking rather than
backward-looking terms?
Given RDFS and WebOnt, we're looking at partial understanding in terms of
RDFS-aware tools dealing with with WebOnt-enriched RDF Schemas (er,
Ontologies). So how about we forget the past and look to the future?
Imagine you're in the WebOnt v3.0 WG, looking back on the products of this
group, balancing v3.0's backward compatibility with present-day
requirements and opportunities. Presumably WebOnt v1.0 isn't the one true
ontology language to end them all? We might expect a version 1.1 or 2.0 at
least. Or perhaps people will take to describing their RDF Schemas and Web
Ontology vocabularies using one of the various RDF-oriented rule
languages. Maybe W3C will even do a REC-track spec or two for such a rule
language. And what about datatyping? The XML Schema WG is still active,
and might well produce refinements of the XML Schema datatyping system,
which will at some point manifest itself in the RDF and Web Ontology
world. The future looks busy.
Partial understanding in action: people will write tools to work with the
WebOnt 1.0 language, just as they're writing tools to work with RDF Schema
vocabulary descriptions now. We need to think about how these new WebOnt
tools will, or won't, be suprised by documents that draw on features
defined in specs subsequent to WebOnt 1.0. Is a WebOnt ontology that draws
upon some additional (webont v2, rdf-rules-1.0?) namespace still really a
WebOnt doc? Is it an RDF Schema for that matter? (re the latter, yes, imho).
At the instance data level, all this shouldn't matter. (Thankfully, for
the poor end users...)
A question. Or maybe even test case...
Is the following XML doc 'mere RDF', or a 'WebOnt instance document'? (or
a DAML+OIL doc). What changes in the Web might change our answers to this
question?
<web:RDF xmlns:web="http://www.w3.org/1999/02/22-rdf-syntax-ns#"
xmlns:wn="http://xmlns.com/wordnet/1.6/" xmlns="http://xmlns.com/foaf/0.1/">
<wn:Person>
<name>Dan Brickley</name>
<mbox web:resource="mailto:daniel.brickley@bristol.ac.uk"/>
<mbox web:resource="mailto:danbri@w3.org"/>
<homepage web:resource="http://purl.org/net/danbri/"/>
<dateOfBirth>1972-01-09</dateOfBirth>
<depiction web:resource="http://rdfweb.org/people/danbri/2000/01/01/Image1.gif"/>
</wn:Person>
</web:RDF>
Note that currently the RDF schema at the http://xmlns.com/foaf/0.1/
namespace asserts that the 'mbox' property used here is a
daml:UnambiguousProperty. At some point it'll probably use WebOnt 1.0
vocab instead. And eventually I'll use whatever ontology, rules and schema
language best capture the intended meaning of the classes and properties
in my namespace. Maybe I won't change the document you get at the
namespace; I might send digitally signed RDF to a usenet group instead.
But the intention should be clear: describe the vocabulary as accurately
as possible with the machinery currently to hand.
Dan
--
mailto:danbri@w3.orghttp://www.w3.org/People/DanBri/